Nearly a quarter of the damages caused by natural disasters in the developing world affect the agricultural sector, exacting a heavy cost on poor farmers who do not have insurance or the resources to rebuild their lives after floods, droughts or other extreme events, the UN’s Food and Agricultural Organisation (FAO) has said.

Between 2003–2013, natural hazards and disasters in developing countries affected more than 1.9 billion people, and caused more than $494bn in damages. Economic losses from natural disasters have tripled over the past decade, and continue to rise.

The FAO analysed 78 post-disaster needs assessments in 48 developing countries during that decade, and found that 22% of all damages were absorbed by the agricultural sector, including crops, livestock, forestry and fisheries – compared to previous assessments of around 13%.

Out of a total $140bn in damages, $30bn affected agriculture, but only 4.5% of post-disaster humanitarian aid in the same period targeted agriculture, it said.

“This (22%) is quite a large number and we think it is underestimated because ... we have been facing a huge data gap ... Yet this 22% is much bigger than results for previous studies,” said Dominique Burgeon, FAO’s resilience coordinator, who is attending the UN conference in Sendai.

In its report, the FAO also compared decreases in yields during and after disasters with yield trends in 67 countries affected by at least one medium- to large-scale event.

Using this methodology, it estimated total damages to crops and livestock over the 10-year period at $70bn. Asia was hardest hit, with estimated losses of $28bn, while Africa registered losses of $26bn.

The FAO found that 82% of production losses were caused by droughts and floods, with 77% of all agricultural production losses worldwide due to drought occurring in 27 sub-Saharan countries and costing those economies $23.5bn.

After natural disasters, trade flows were also jolted, the FAO said, noting an increase of $18.9bn in agricultural imports, and a decrease of $14.9bn in exports after natural disasters in the countries it surveyed.

Around 50% of global food production is produced by 2.5 billion smallholders. We have a huge challenge ahead

Dominique Burgeon, FAO

Around 2.5 billion small-scale farmers, herders, fishermen and forest communities depend on agriculture to survive, and their labours account for more than half of global agricultural production.

“We know we need to increase global food security by 60% ... Bearing in mind that around 50% of global food production is produced by these 2.5 billion smallholders, we have a huge challenge ahead of us, and an increasing number of disasters affecting these people,” Burgeon said.

The FAO announced it was launching a special facility to help countries reduce risk and limit impacts of natural disasters in food production sectors. Under this new scheme, technical support will be provided to those who need it most.

“One thing that is emerging is countries’ realisation that they have to make sure that the risk dimension is mainstreamed into their sectoral policies – livestock, crops and fisheries,” Burgeon said.

“We consider that for a country to adjust its policies accordingly, you need six to nine months and therefore there is a cost involved to organise the capacity development, (and) the training ... so that people can own the process,” he said.

The FAO has estimated the cost at around $500,000 per country, and Burgeon said they needed $10m to be able to support 20 countries to start this process.

The importance of disaster risk reduction took on a particularly poignant relevance in Sendai, where the president of Vanuatu, Baldwin Lonsdale, spoke on Monday of the devastation caused by cyclone Pam, which ripped through the Pacific island nation of mainly subsistence farmers at the weekend.

Lonsdale said climate change was contributing to more extreme weather conditions and cyclone seasons.

“This is a very devastating cyclone … I term it a monster that has hit Vanuatu,” he said. “It is a setback for the government and for the people of Vanuatu … All the development that has taken place has been wiped out.”

Around 4,000 government officials and civil society participants are in Sendai, which was devastated by a tsunami and earthquake four years ago, to agree a new protocol to update the Hyogo Framework for Action, adopted 10 years ago in Kobe, Japan.